arrrghhh

iTrader: (2)

So my girlfriend brings my '96 maxima home yesterday and says it won't rev past 2500 rpms... OK. So I drive it around and sure enough the car does not rev past 2500.

I pulled the codes, P0100 was the error. MAF or VAF... Not sure what a VAF is, but I do know what a MAF is. It's $300 from checkers and $600 from the stealership.

I want to make damn sure this is the culprit basically. Anything else that could be causing it? I cleared all the codes and that's the only one that came back. (There was one other for an O2 sensor...)

I figure I should check for voltage in the plug going into the MAF right? How much should I see? Like I said, I don't really want to drop $300 on a part that isn't going to fix it...

Thanks in advance for any help/advice!!

eFLO

iTrader: (2)

you can get a maf cheap hit up the classified section, i'm sure someone has one fs

arrrghhh

iTrader: (2)

Hrm... then I have to wait for something that may or may not fix the car...?

Not really a solution. She kinda needs the car to get to work unfortunately.

If it is the MAF, I'll probably just suck it up and go to checkers and buy it, just because I need the car back up & running ASAP unfortunately...

eFLO

iTrader: (2)

you said you got the code for a faulty maf sensor, how would fixing the maf sensor not fix your problem?
if you want to try, buy some maf cleaner spray it see what happens..

arrrghhh

iTrader: (2)

Well it could also be wiring, and it could just be dirty. I wanted to make sure I was getting proper voltage etc at the plug to be sure it wasn't anything else silly like a relay, fuse, what-have-you.

eFLO

iTrader: (2)

fwiw, voltage at idle should be 1.0-1.7

bkortee

clean your maf before you do anything else.

arrrghhh

iTrader: (2)

Excellent, thank you. I'll check that after cleaning the MAF and TB. Not sure if I'm going to clean the IACV and EGR...

Agreed. Goin to auto parts store now to get that cleaner!

arrrghhh

iTrader: (2)

Alright guys. I cleaned out the MAF and the TB. Not really much to speak of on either, and it didn't have an effect.

So I bit the bullet and bought a new MAF since that's what the code on the OBDII seem to point to...

However, after a shiny new MAF from AutoZone (found it cheapest here!) I still have the issue. The check engine light hasn't come back on yet, but the OBDII registers the same failure - P0100, MAF or VAF sensor circuit failure. Is there a fuze associated with this anywhere? I couldn't find one. I pulled a few that I thought would be related, but no blown fuses that I can find.

So far I'm out about $260, and unfortunately I don't think they'll take the MAF back. What should I check next guys? I couldn't get voltage on the plug, but I couldn't really get my volt meter to make contact either... Thanks!!

I'm going to leave the battery d/c'd to see if it resets the computer... If it is the wiring, what can I do? Visually the wiring looks fine. I certainly can't see any frayed or otherwise exposed/damaged wires...

Trini Boom

iTrader: (5)

They will take the MAF back if you tell them you no longer need it with a receipt of course. Also, your harness could be anything from the ECU to the MAF itself. You have to check that you are getting a reading at both ends.

arrrghhh

iTrader: (2)

They took a core charge on the MAF and said they would not accept a return... they would swap it out if it's faulty, but would not return it. Plus, they now have my old MAF because of the core charge.

How can I get a reading at both ends? I can't even get a reading at the end that should be simple - right at the plug.

eFLO

iTrader: (2)

What do you mean you "couldn't make contact"?
I suppose if the new maf doesn't workvthe issue with the harness, or if your luck is bad enough you bought a defective

Trini Boom

iTrader: (5)

So when you turn the key to ON and try reading the voltage coming through at the harness, you are getting nothing??

eFLO

iTrader: (2)

connect your volt meter + lead to the red wire on the plug coming from harness, ground the - lead. as triniboom said turn the key to ON, you should be getting around 12V.

to test the maf connect it to the harness, turn the car on, and test the white wire on the maf connector, it should read 1-1.7 volts at idle.

arrrghhh

iTrader: (2)

I'm sorry... I have not really troubleshot any electrical issues on a car before.

There's no exposed metal to put the probes on my voltmeter onto - that's my problem.

When I pull the plug off the MAF, I can't seem to quite get the probes onto any metal inside the plug. When the plug is on the MAF, I don't have any exposed metal - where do I put the probe up to ?

If the MAF is defective, AutoZone will replace it for me - that much they did guarantee. Refunds, not so much... I took the risk knowing full well, I'm just desperate to get this thing back on the road. Thanks again guys.

jholley

iTrader: (13)

^^

Slide a small metal object like a bent paperclip into the connector then lean the probe against that metal object.

arrrghhh

iTrader: (2)

Have you actually tried this? It sounded like a good idea to me, but it in reality it is a HORRIBLE idea. I found out the hard way that behind those screws that plug is SOLDERED to the MAF sensor. So I basically just broke the hell out of this MAF. I can test the wiring now tho!! Hooray! Hopefully AutoZone will exchange it for me...

This does give me a great place to test from however. I'm still not getting any voltage. Car is not running, key is turned to ON. I put red to red, black to ground, nothing. Tried every other possible combination I could, still nothing. Kept testing the voltmeter straight on the battery to make sure I wasn't crazy. Even tried switching it over to AC, still nothing. I assume the power coming out of the plug would be DC... yes? Ugh. If I'm not getting voltage at the plug what could be wrong? Is there a fuse I missed? The wiring visually looks fine but it goes straight into a huge bundle obviously...

eFLO

iTrader: (2)

hopefully this diagram will help. connect everything. start the car etc, as pictured above.
basically you want to run the paperclip, pin, whatever you use along the side of the wire until you contact the terminal, at which point you can test the voltage

arrrghhh

iTrader: (2)

OK, I didn't realize it was alright to shove something into that side... That's why I was so confused as to how to check voltage when it's plugged in - I thought shoving something in that side would hurt the wiring, or potentially leave the plug open to water damage.

I'll go check it again... but I think I was making contact on the plug when it wasn't plugged in - just had the car turned to ON but it wasn't running - I was getting absolutely nothing. If it is this wiring, how can I fix it? I have no clue where the far end goes, that's why I was hoping it was a fuse or relay that's blown...

Thanks again for your help guys, I'm more of a computer troubleshooter than a car troubleshooter. More of a car 'enthusiast' - as in I worry that my tinkering will end up breaking stuff!

arrrghhh

iTrader: (2)

Ok, so with a very thin piece of wire shoved into the back of the plug on the white wire... I get no voltage. I'm taking the red probe on my voltmeter and hooking it up to that exposed wire coming out of the white wire... I flipped it around a few different ways to see if I could get any change. Hopefully I didn't damage the MAF... I did get voltage when I put my negative (black) probe to the white wire and the positive (red) probe to the positive on the battery, but the rpms would dip so I assume I was just sending voltage thru the MAF from the battery - and the reading was just the reading from the battery itself.

So it does seem like wiring. What's next? Like I said visually the wiring looks fine, but it just goes directly into a big bundle of wire...

Any help is greatly appreciated, I need to get this thing running! Thanks again!

jholley

iTrader: (13)

Copy over the Engine Control System file from this website:

http://www.nicoclub.com/FSM/maxima/1998/EC.pdf

Scrolling thru pages EC-110 to EC-116 will give you a description and troubleshooting guide of this MAF sensor.

I would check the BLK wire for its continuty. On my DIG multimeter any reading over 0.5 ohms is a dirty GND connection. Compare the voltages you get straight from the battery to the volatge reading on the red wire with the IGN on. With a clean volatge wire you should get no more than 0.5V difference.

ImprezaRx7Lvr

yeah sounds like a problem i had when my MAF went out and I just replaced mine, cleaned the air filter, reconnected everything and it ran fine again, good luck with your specific problem though... right now I'm dealing with what might be a blown head gasket http://forums.maxima.org/7649822-post6086.html

FallenOne

iTrader: (17)

arrrgh, I hate to tell ya but it sounds as if your ECM could be going.

If you have checked the Wiring harness and the MAF.. You could potentially have a bad ECM...

To my knowledge there are No other components that can cause an MAF sensor to Ghost a code... I would take the MAF back to Autozone and tell them you want a diffrent one as the only other alternative i see at this point is the possibility that they sold you a blehm.

99zx2

iTrader: (3)

your + to the battery and negative to maf didn't do any good, since you were reading the battery's voltage.

did you ground the negative one when you did this?

cashoit

Stop spending money needlessly man. Test MAF and ECM per FSM. Can only be 4 things, either MAF shot, wires shorted, Connector shot, or ECM shot.

clean grounds on the engine.

arrrghhh

iTrader: (2)

Yes.

I agree completely. I'll check the grounds. I'll look at the FSM's to see how to check the ECM... not sure how to do that. Alrighty, I looked over the FSM and it's making a little more sense. I still don't get how to check the voltage at the ECM itself however...?

Hrm, don't like the sound of that. I did take it back to AutoZone and swapped it for another one, same issue... So it definitely seems like wiring somewheres...

I was unable to get any voltage on the red wire with the IGN on... I'll try again when I get home tonight, but in my testing I was not able to get any voltage on the red wire.


The post count that this post brought about for me... just way too appropriate. (It was 666 )

Also just spoke to my mechanic, he suggested I start checkin fuses... I couldn't find a related fuse, but I guess I'll just start checkin all of them. He also said that if the car is in LIMP mode that the ECM is still functional... Perhaps the wire from the MAF to the ECM is bad, no telling yet.

Vqpwred

Hey i had the same problem and mines did the same i have a working maf and o2 I have a 96 my self so let me know

arrrghhh

iTrader: (2)

Well, read the rest of the thread... it seems like mine is electrical, I can't get any voltage at the plug. Do the steps that were recommended to me - I'm just a n00b when it comes to troubleshooting automotive issues, so I don't know where I should be testing from/on.

99zx2

iTrader: (3)

try wiggling the plug and see if the voltage changes any. inspect the wires for wear.

arrrghhh

iTrader: (2)

For me, wires *look* fine. No exposed metal or anything that would indicate a fault (to me). Wiggling has not had an effect on voltage... but again, I have no clue where these wires end up in the ECM or if there's a particular fuse/relay I should check...

jholley

iTrader: (13)

Page EC-114 defines the MAF volatge source is from ECCS relay. This relay is loacted in front of the battery. With a thin flat headed screw driver pop up that relay. With the IGN ON check pins 2 & 3 for voltage. If you do get 12V then either the relay is bolwn, the ECM is malfunctioning, or the wire connecting the relay to the MAF is shorted. Check for continuity between pin 5 of the relay to the MAF's red wire. If you don't get 12V then the volatge wires feeding that relay box need to be checked.

Capitone

iTrader: (1)

Just wanted to make sure I'm reading you right. By "same issue" your referring to your revs still not going over 2500 right? Just reading it, it almost sounds like your referring to just the codes....just wanted to make sure.

arrrghhh

iTrader: (2)

Excellent, thank you. I will check this tonight.

Both. Still getting P0100, and engine still in LIMP mode - fuel cuts at about 2500 rpms. FSM says 2400 rpms, either way.

jholley

iTrader: (13)

In case you didn't know the ECCS relay is labelled as EGI in the lower left corner of the relay box.
You might also need to check for continuity bewteen that relay and the ECM. You'll find the troubleshooting guide for this in the engine control system manual right before those MAF pages.

arrrghhh

iTrader: (2)

Cool, thank you. Have my lappy in the garage testing stuff now... Damn I wish I could find my "good" (relative term...) voltmeter!!

Ok... It looks like I'm getting about 12v from the ECCS relay - put red to #1 black to #2 and I get voltage!

So I'm guessing there's an issue between the plug and that relay box? On EC-114 I'm not sure what's inbetween the ECCS relay and the plug itself... is that just the connection back to the ECM?

jholley

iTrader: (13)

The EGI relay is jointly connected to both the MAF plug and the ECM. The engine control systems manual will show you that. Before you check those wires swap that relay with the FAN1 relay. You could just have a blown relay.

Check out page EL-304 of this manual:

http://www.nicoclub.com/FSM/maxima/1998/EL.pdf

It lays out the harness you may have to troubleshoot.

arrrghhh

iTrader: (2)

Is it ok for me to start the car without that FAN1 relay? Or should I just test that red wire for voltage when the ignition is ON?

Thanks again for the help!. At this point I'm just narrowing it down for a professional... I don't think I'll be able to repair any harness wiring on my own...

Trini Boom

iTrader: (5)

It is ok for you to start the car without the relay or if you feel safer, swap it with an identical one there. Also, its up to you if you want to fix the harness yourself. You are a computer guy just like myself and we can guide you in exactly what you need to do. Have faith in the .org

arrrghhh

iTrader: (2)

Well if someone can help me fix the harness I'd love it. Just struggling thru troubleshooting at this point! I'll try the relay trick and report back.

Swapped relays, problem persists. CEL gets rethrown after clearing it, and no voltage still at the plug that goes into the MAF...

jholley

iTrader: (13)

Do as I said in an earlier post and check for continuity between pin 5 of the EGI relay to the MAF red wire. If you don't get continuity then you'll have to troubleshoot the wiring from the relay to the MAF. If you do get contiuity then it's the ECM that needs to be troubleshooted.